C++ make_shared not available

Question

While I have std::tr1::shared_ptr available in my compiler, I don\'t have make_shared.

Can someone point me to a proper implementa

Answer 1

If your compiler don't give an implementation of make_shared and you can't use boost, and you don't mind the lack of single-allocation optimization both for the object and the reference counter then make_shared is something like this:

Without variadic template support:

// zero arguments version
template 
inline shared_ptr make_shared()
{
  return shared_ptr(new T());
}

// one argument version
template 
inline shared_ptr make_shared(Arg1&& arg1)
{
  return shared_ptr(new T(std::forward(arg1)));
}

// two arguments version
template 
inline shared_ptr make_shared(Arg1&& arg1, Arg2&& arg2)
{
  return shared_ptr(new T(std::forward(arg1),
                             std::forward(arg2)));
}

// ...

If your compiler don't support r-value references, then make 2 versions for each arguments count: one const Arg& and one Arg&

With variadic template support:

template 
inline shared_ptr make_shared(Args&&... args)
{
  return shared_ptr(new T( std::forward(args)... ));
}